Long QT Syndrome Among Patients With RA

The 5-year absolute risk of incident long QT syndrome among patients treated with hydroxychloroquine for rheumatoid arthritis was very low, providing evidence that long-term use of the therapy is safe, researchers reported in Arthritis Care & Research.

Although recent evidence shows no association between treatment of rheumatoid arthritis (RA) with hydroxychloroquine and a higher 1-year risk of long QT syndrome (LQTS), the long-term risk of this cardiac disorder was not well known, the investigators pointed out.

The researchers conducted a propensity score-matched, active-comparator safety study of hydroxychloroquine among veterans newly diagnosed with RA. The study subjects had a mean age, 64±12 years; 14% were women and 28% were African Americans. Of 8852 patients, 4426 patients began treatment with hydroxychloroquine while 4426 initiated therapy with another nonbiologic disease-modifying antirheumatic drug (DMARD). These cohorts were balanced on 87 baseline characteristics. The primary outcome was LQTS during the 19-year follow-up period, which ended December 31, 2019.

“Incident LQTS occurred in 4 (0.09%) and 5 (0.11%) patients in hydroxychloroquine and other DMARD groups, respectively, during first 2 years. Respective 5-year incidences were 17 (0.38%) and 6 (0.14%), representing 11 additional LQTS in hydroxychloroquine group (number needed to harm, 403; 95% CI, 217–1740) and 181% greater relative risk (95% CI, 11%–613%; p=0.030),” the investigators wrote. “Although overall 10-year risk remained significant (hazard ratio, 2.17; 95% CI, 1.13–4.18), only 5 extra LQTS occurred in hydroxychloroquine group over the next 5 years (years 6–10) and 1 over the next 9 years (years 11–19). There was no association with arrhythmia-related hospitalization or all-cause mortality.”

Hydroxychloroquine use had no association with LQTS during the first 2 years after initiation of therapy, the researchers concluded. Although a higher, significant risk was found after 5 years of therapy, they found, “the 5-year absolute risk was very low, and the absolute risk difference was even lower. Both risks attenuated during longer follow-up. These findings provide evidence for long-term safety of hydroxychloroquine in patients with RA.”

—Rebecca Mashaw

Reference:

Quiñones ME, Joseph JK, Dowell S. Hydroxychloroquine and risk of long QT syndrome in rheumatoid arthritis: A veterans cohort study with 19-year follow-up. Arthritis Care Res.

Published online August 30, 2022. DOI: https://doi.org/10.1002/acr.25005